Apolipoprotein A1 (APO A1) has been reported to be a better predictor than HDL cholesterol and triglycerides for Coronary Artery Disease (CAD). Low levels of APO A1 in serum are associated with increased risk of CAD. The measurement of APO A1 may be of value in identifying patients with atherosclerosis. Apolipoprotein B (APO B) has been reported to be a more powerful indicator of CAD than total cholesterol or LDL cholesterol in angiographic CAD and in survivors of myocardial infarction. In some patients with CAD, APO B is elevated even in the presence of normal LDL cholesterol.

There is a correlation between increased risk of premature heart disease with decreasing size of LDL particles. Ion mobility offers the only direct measurement of lipoprotein particle size and concentration for each lipoprotein from HDL3 to large VLDL.

To screen for and monitor kidney dysfunction in those with known or suspected kidney disease. Cystatin C is a relatively small protein that is produced throughout the body by all cells that contain a nucleus and is found in a variety of body fluids, including the blood. It is produced, filtered from the blood by the kidneys, and broken down at a constant rate. This test measures the amount of cystatin C in blood to help evaluate kidney function.Cystatin C is filtered out of the blood by the glomeruli, clusters of tiny blood vessels in the kidneys that allow water, dissolved substances, and wastes to pass through their walls while retaining blood cells and larger proteins. What passes through the walls of the glomeruli forms a filtrate fluid. From this fluid, the kidneys reabsorb cystatin C, glucose, and other substances. The remaining fluid and wastes are carried to the bladder and excreted as urine. The reabsorbed cystatin C is then broken down and is not returned to the blood.

Serum glucose levels may be abnormally high (hyperglycemia) or abnormally low (hypoglycemia). Glucose measurements are used in the diagnosis and treatment of carbohydrate metabolic disorders including diabetes mellitus, idiopathic hypoglycemia, and pancreatic islet cell neoplasm.

Serum iron quantification is useful in confirming the diagnosis of iron-deficiency anemia or hemochromatosis. The measurement of total iron binding in the same specimen may facilitate the clinician''s ability to distinguish between low serum iron levels caused by iron deficiency from those related to inflammatory neoplastic disorders. The assay for iron measures the amount of iron which is bound to transferrin. The total iron binding capacity (TIBC) measures the amount of iron that would appear in blood if all the transferrin were saturated with iron. It is an indirect measurement of transferri

A lipid panel includes:Total cholesterol —this test measures all of the cholesterol in all the lipoprotein particles.High-density lipoprotein cholesterol (HDL-C) — measures the cholesterol in HDL particles; often called "good cholesterol" because it removes excess cholesterol and carries it to the liver for removal.Low-density lipoprotein cholesterol (LDL-C) — calculates the cholesterol in LDL particles; often called "bad cholesterol" because it deposits excess cholesterol in walls of blood vessels, which can contribute to atherosclerosis. Usually, the amount of LDL cholesterol (LDL-C) is calculated using the results of total cholesterol, HDL-C, and triglycerides.Triglycerides — measures all the triglycerides in all the lipoprotein particles; most is in the very low-density lipoproteins (VLDL).Very low-density lipoprotein cholesterol (VLDL-C) — calculated from triglycerides/5; this formula is based on the typical composition of VLDL particles.Non-HDL-C — calculated from total cholesterol minus HDL-C.Cholesterol/HDL ratio — calculated ratio of total cholesterol to HDL-C.

Clinical Significance

Lipoprotein-associated phospholipase A2 (Lp-PLA2), also known as platelet activating factor Acetylhydrolase, is an inflammatory enzyme that circulates bound mainly to low density lipoproteins and has been found to be localized and enriched in atherosclerotic plaques. In multiple clinical trials, Lp-PLA2 activity has been shown to be an independent predictor of coronary heart disease and stroke in the general population. Measurement of Lp-PLA2 may be used along with traditional cardiovascular risk factor measures for identifying individuals at higher risk of cardiovascular disease events. Clinical management may include beginning or intensifying risk reduction strategies. The activity assay is an enzyme assay run on an automated chemistry platform.

Patients with vascular diseases will generally have either a C-ANCA pattern or P-ANCA pattern, and give positive results in specific tests for PR-3 or MPO. Patients with bowel disease have been shown to have antibodies that give a P-ANCA or C-ANCA pattern. These antibodies, however, may not be directed toward MPO. Patients with drug induced lupus, etc., often present with a P-ANCA pattern that is associated with antibodies against MPO.

For differential diagnosis of primary, secondary, and tertiary hypothyroidism. Also useful in screening for hyperthyroidism. This assay allows adjustment of exogenous thyroxine dosage in hypothyroid patients and in patients on suppressive thyroxine therapy for thyroid neoplasia.